The present invention relates to a front airbag, especially a passenger airbag.
With airbags, depending on the interior dimensions and the contour of the adjacent surfaces (especially of the instrument panel) airbags having different characteristics are used. In the case of very plane surfaces and simple contours the so called two-dimensional airbags are used that can be manufactured at lower cost. With these airbags it is possible to manufacture the airbag from a one-piece fabric part which then is folded and sewn up at edges adjacent by folding. However, such two-dimensional airbags are suited for rather simple contours as mentioned already. What is important with the airbag is that upon impact of the occupant it can contact an adjacent vehicle part and can rest thereon.
Moreover it is desirable that the seams are not thermally overloaded.
Hereinafter, the term “seam” preferably focusses on actually sewn-up edges, wherein this is not restrictive, however, as there are already welded or glued seams and these are likewise to be understood by “seam”.
An example of a so called two-dimensional airbag is given by U.S. Pat. No. 5,316,337.
Moreover, there are also the so called three-dimensional airbags in which the airbag has an outer contour that is more complex in the inflated state and consists of plural sewn up individual parts, especially of two side walls and a strip-shaped peripheral central part which interconnects the side walls so that sort of a roller is resulting which need not take the shape of a circular cylinder but may have any shapes depending on the geometry of the side walls. Such three-dimensional airbags are more difficult to sew as the edges to be sewn up are not overlying by just folding the airbag fabric.
From WO 2010/05760 A1 furthermore a passenger airbag having a design which can be adapted to different interior contours is known.
New limits e.g. concerning the strict US-NCAP crash test for maximum loads for occupants require adaptations of the known airbags so that they may further be assessed to rank first.